A possible plot is that Zelda herself is transported to RWBY's Vale. She has her magic and wisdom, but she needs to adapt to this new world. She meets Team RWBY and they initially don't trust her. But as she starts to show her knowledge of magic and combat, they realize she can be an asset. Together, they face off against a new threat that is endangering both the Zelda universe and RWBY's world.
Maybe the Triforce from Zelda gets scattered across the RWBY world. Ruby, Weiss, Blake, and Yang set out on a journey with Link to find the pieces. Along the way, they encounter various Zelda - like dungeons in RWBY locations. Link teaches the RWBY girls his combat skills, and they in turn show him how to use Dust, creating a really cool exchange of abilities.
One interesting plot could be that the heroes from The Legend of Zelda, like Link, find themselves in the world of RWBY. Link might have to team up with Ruby and her friends to fight a new common enemy that is a fusion of the dark forces from both universes. For example, Ganon's magic combines with Grimm energy to create a super - powerful and menacing foe.
One possible plot could be that Link finds himself in the Marvel universe. He teams up with Spider - Man to stop Ganondorf, who has made a deal with some villains in the Marvel world to gain more power. Link uses his sword skills and Spider - Man uses his webs and agility to fight off Ganondorf's minions and ultimately face the big bad himself.
It could be about Link ending up in Equestria and teaming up with Twilight Sparkle to fight a new evil that threatens both their worlds. Maybe Ganondorf has found a way to enter Equestria and is causing chaos, and Link uses his combat skills while Twilight uses her magic to drive him out.
Well, one possible plot could be that Sailor Moon and her friends get transported to the world of Legend of Zelda. They could team up with Link to fight against a common enemy like Ganon who has somehow allied with the Dark Kingdom from Sailor Moon. Sailor Moon could use her powers to heal Link when he gets injured in battles, and Link could teach the Sailor Scouts some of his combat skills.
Another interesting pairing could be Ganon and Salem. Both are powerful villains in their respective universes. They could form an alliance in the crossover fanfiction. Ganon's brute strength and dark magic combined with Salem's cunning and ability to manipulate would create a truly terrifying force. And the heroes from both worlds would have to work together to stop them.
One idea could be Link crossing over into a modern world. He'd be confused by the technology like cars and cell phones. Another could be Link teaming up with a character from another game, like Mario. They could combine their skills to defeat a common enemy.
Some fanfictions might explore the idea of the Triforce in the RWBY universe. Suppose the Triforce represents a powerful force that could either help or harm Remnant. The characters from both worlds would be drawn to it. The Zelda characters, with their knowledge of the Triforce, would have to work with RWBY's Huntsmen and Huntresses to protect it from falling into the wrong hands. There could also be a situation where Zelda's dungeons are reimagined in the RWBY world, and the RWBY teams have to go through them to achieve a certain goal.
One interesting plot twist could be that characters from Fairy Tail end up in the world of Legend of Zelda and they discover that their magic has a completely different effect. For example, Natsu's fire magic might interact with the magical elements in Zelda's world in a way that either helps or hinders their quest. Another could be that the Triforce has an unexpected reaction to the Fairy Tail mages' presence, perhaps granting them new powers or cursing them. A third plot twist might be that a major villain from Legend of Zelda teams up with a dark guild from Fairy Tail to take over both worlds.
One possible plot could be that Doflamingo somehow ends up in the RWBY world. He might initially try to take over, using his strings to manipulate the Grimm. But the RWBY team discovers his true nature and battles him. Ruby could use her speed to avoid his string attacks while Weiss uses her glyphs to counter his powers.
Another plot could be that an evil force in the RWBY universe discovers the existence of the Omnitrix from another dimension. They manage to create a device to pull Ben and the Omnitrix into their world. Ben has to adapt quickly to this new world while Team RWBY, who are initially suspicious of him, realizes that he could be an ally against this new threat. They join forces, with Ben using his alien forms in creative ways to combat the Grimm and the evil force's minions.
A possible plot is that the RWBY characters end up in New York. Ruby, with her speed and scythe skills, is initially mistaken for a threat by Spiderman. But when they realize they are both on the side of good, they join forces. Weiss could use her glyphs in new and creative ways in the urban environment, Blake's stealth and acrobatic skills could be put to great use, and Yang's strength would be a valuable asset. Together they take on a criminal organization that has somehow gotten hold of some Dust and is using it for evil purposes.